The objective was to study different groups of bacteria that can adapt to extreme conditions of temperature, pH and salinity, as well as to identify bacterial strains from cultivated (CS) and noncultivated (US) soil samples collected in the city of Brazlândia, Brazil. 38 strains were collected and submitted to growth tests at 45, 55, 65 and 75ºC, pH of 3, 4, 5, 9, 10 and 11 and salinity of 5, 10 and 15% of NaCl. Eleven strains were selected based on their biochemical characterization and identified based on their 16S rDNA sequences. Four groups of bacteria in the CS and US samples were identified and able to grow under the most extreme conditions. Eleven bacterial strains were